While I don't know any billionaires, the wealthy people I knew while I was a financial manager fit this profile exactly.
They lived in a nice home within, but not above, their means. Their automobiles were nice, but they drove them for a very long time - generally speaking 10 years or more. They contributed to charity, but did so quietly and without fanfare so not to attract others who would harass for money.
They encouraged their children to work towards scholarships, and their children worked in college to help offset costs.
I've followed their example to secure a future for my own family, and to leave a legacy for my son. We live comfortably and are blessed, but we do not squander.
The people you described fit exactly the profiles in the book, “The Millionaire Next Door.”
JUST SO!
Well done!